Merge pull request #18594 from fredriss/dev/rdar-43011380-lldb-deployment-target

Force teh deployment target of LLDB to 10.13
diff --git a/utils/build-script-impl b/utils/build-script-impl
index 43433aa..ac1f644 100755
--- a/utils/build-script-impl
+++ b/utils/build-script-impl
@@ -1762,6 +1762,7 @@
         OBJROOT="${lldb_build_dir}"
         -UseNewBuildSystem=NO
         ${LLDB_EXTRA_XCODEBUILD_ARGS}
+        MACOSX_DEPLOYMENT_TARGET=10.13
     )
     if [[ "${LLDB_NO_DEBUGSERVER}" ]] ; then
         lldb_xcodebuild_options=(